That's not how most atheists see it. They take morality seriously, and often reject survival of the fittest--hence their cynicism of capitalism. Just because it worked for nature, doesn't at all mean it's a good idea for structuring society. Atheism doesn't mean moral relativism. In fact many atheist could be accused of being morally righteous. I'm like Brock. I don't know what I believe as far as afterlife, creation, and spirituality. But I do try to be a good person, and I guess I do that through I trial and error. But it really drives me up the wall when people question my/our sincerity because I don't believe in your God, as if it take believing in God to be a good person. The people who are genuinely good do it for the act itself, and need no approval of religion or promise of heaven.